I’m running a big-block 440 that was completely rebuilt to stock specs at first. When I got the car, I upgraded the engine by having the iron heads swapped for a set of CNC ported Edelbrocks, and added a Comp XE282S solid lifter cam lift and a set of Crane 1.6 rockers. I also added a set of Hooker headers, and a full 3-inch exhaust system with MagnaFlow straight-through mufflers. The engine really picked up with these changes, and I’m happy with the performance. That’s not the problem. The problem is that when I had the engine apart, I saw that it was rebuilt using a set of cheap stock-replacement cast pistons.
The engine makes power, and sometimes I like to rev it over 6,500 rpm. It doesn’t lie down, it just keeps on pulling. I’m just a little worried that the pistons aren’t good enough. I don’t want this engine to blow up, since I already have a lot of money into it, and probably couldn’t afford to build up another one. So far, the engine has been great, so I’m wondering if I’m worrying about nothing. After all, I’ve even had it close to 7,000 rpm, and it was just fine afterwards, so I guess the pistons have passed the test. What do you guys think?
Frank Simpson - Via moparmuscle.com
As much as we like to encourage high-winding abuse, in good conscience I would have to recommend you take it easy with those high rpm blasts, or get new pistons. Here is a universal truth in the high performance engine world: cheap stuff works great until the day it breaks. Cheap, cast replacement pistons are just that—replacement parts. They are not racing parts or even high performance parts—they are replacements for stock parts and sometimes not even as good as the OEM components. The material that regular cast pistons are made of is brittle, and subject to sudden and catastrophic failure. Forged pistons are made of a much more forgiving material, and will deform if over-stressed, whereas a cast piston will shatter like shrapnel. There won’t be any warning, and just because you’ve gotten away with it before is no way guaranteeing that it won’t let go the next time. It’s just a roll of the dice.
I once built a hot little 360 Mopar small-block using bargain cast pistons for their low price. The engine was a real screamer in a truck - fast enough to take out my buddies 400-equipped GTO. It made awesome power, right up until the day a piston exploded, taking the entire engine with it. Lesson learned.
I have a ’71 Road Runner with an automatic and a 383. It also has A/C, in case it matters. It has an Orange box electronic ignition upgrade, and an MSD 6AL box. I think the orange box was disconnected or bypassed when the MSD was installed? Not sure, since my friend installed the MSD.
Prior to the install of the MSD, my lights would dim when I put the car in gear, but would brighten when driving or when increasing the rpm. Also, the Amp gauge would stay fixed to the right of center somewhere.
After the MSD was installed, I don’t really notice the lights dimming as much, but all the lights (dash, headlights, and tail lights) seem to pulse slightly when on. The Amp gauge mostly moves back and forth in a rhythmic pattern like if counting “one thousand one,” “one thousand two” etc. And sometimes the gauge even stops moving for a short while.
Chris Kolak - Via email
Chris, I don’t think the MSD is the source of your problem. I would start with the charging system. With the battery fully charged, try disconnecting the voltage regulator and see if the pulsing continues. It will probably go away, indicating the problem is in the charging system. Make sure the regulator is well grounded and the connections are clean. If the problem persists, you may want to try a new regulator. The alternator could also be the source of the problem, and it would be a good idea to have it tested.
The stock Mopar charging system of the era was really marginal. The problem is all the current goes in and out through a connection at the bulkhead connector and then through the alternator. All these connections have a tendency to burn up in time from excess current load and too much resistance. I don’t know if keeping your Road Runner dead stock is a priority, but bypassing the bulkhead connector and running a new heavy gauge charge wire directly to the battery terminal of the starter relay is a common modification. If you want to keep it all stock and your wiring is marginal with signs of overheating at the bulkhead connector, consider new harnesses.
Is there a head that will bolt on to a 440 that will change it to a Hemi type engine? Stage VI (sic) maybe? What do I need to watch out for? Also, for just street/strip, what is a good manifold/carb setup for this? I am thinking of putting this combo into a Crossfire. Is this an easy install? What other chassis’ would this be a good install for? I would still like an A-Body.
Steve Koziatek - Via email
Steve, a company called Stage V Engineering at one time made Gen II Hemi heads that where designed to bolt onto a Wedge big-block. There was a small market for this conversion back in the ’80s when all we had were original Hemi blocks, and they were in very short supply. With aftermarket Hemi blocks coming out, that conversion faded out as it was no longer necessary, nor the best route to Hemi power. If it is a Hemi you want, you’re far better off getting a real Hemi block. As far as a chassis to put the Hemi into, I think you are pretty much on your own with the Crossfire idea. It is going to be a full custom swap, and might be best accomplished with a tube chassis conversion. If it were me, I would gravitate towards a car that received the Hemi in production, like a B or E-Body Mopar. The Hemi can be installed in an A-Body, though it is tight. I have always wanted a ’68 Hemi A-Body clone.
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